Anodic assembly for electrolysis cells

ABSTRACT

An assembly for use in electrolysis cells including a permanent, rigid, inert and reusable base which has the form of a square open tank with only three sidewalls; and, an anodic aggregate set down on this base without an fastening means. This aggregate is composed of graphite anodic plates, anodic bars and the fourth sidewall of the base. All metallic parts of the assembly are protected by a covering which also embodies the fourth sidewall. The tightness between the fourth sidewall and the base is insured by a flexible seal.

nite d States Patent Giacopelli 1 5] Feb. 15, 1972 [54] ANODIC ASSEMBLYFOR 3,425,929 2/1969 Emery et a1 ..204/286 X ELECTROLYSIS CELLS2,865,834 12/1958 Ross ........204/266 3,498,903 3/1970 Kamarjan..204/266 1 memo g 'zg v hx Roslsnano- 2,370,087 2/1945 Stuart ..204/286x o vay, ivomo a y 22] in Dec. 23 19 9 Primary Examiner-John H. MackAssistant Examiner-Regan J. Fay l PP 887,527 Attorney-Robert E. Burnsand Emmanuel J. Lobato [301 Foreign Application Priority Data [57]ABSTRACT An assembly for use in electrolysis cells including a per- Dec.80, 1968 Belgium ..681S6 manem rigid, inert and reusable base which hasthe form of a square open tank with only three sidewalls; and, an anodicag- '8 g gregate set down on this base without an fastening means. Thisaggregate is composed of graphite anodic plates, anodic bars [58] Fieldof Search ..204/266, 286, 288, 289 and the fourth sidewall ofthe base-A" metallic p of the sembly are protected by a covering which alsoembodies the [56] (defences cued fourth sidewall. The tightness betweenthe fourth sidewall and UNITED STATES PATENTS the base is insured by aflexible seal.

Kircher ..204/286 x 8 Claims, 7 Drawing Figures PATENTEB FEB 1 5 I972saw 1 or 5 PAIENTEDFEM 5 I972 SHEET UF 5 ANODIC ASSEMBLY FORELECTROLYSIS CELLS This invention concerns a new anodic assembly forelectrolysis cells where anodes and cathodes are interleaved and areespecially used to electrolize aqueous solutions of alkaline metalhologenides.

In conventional cells of this type, the anodic plates are made ofgraphite and are vertically settled in a reinforced concrete base. Theyare set in a bed made of leader a low melting point alloy. Conductivebars supply the electric current and are embedded in contact with thebottom of the anodic plates. An inert covering protects this lead oralloy bed against an attack of the electrolyte or of the electrolysisproducts. When used, the anodic plates become thinner and thinner andmust be replaced periodically. However, the lead or alloy and theconductive bars may only be recovered by destroying the base.

Belgian Pat. Nos. 674,452 and 708,888 relate to improvements toconventional assemblies. These improvements consist essentially inmelting the embedding material by means of the Joule effect, and thenusing a low melting point alloy, such as a lead-bismuth alloy. Thesealloys are much more expensive than lead which is generally used as theembedding material, and the materials used to manufacture the base mustwithstand the melting temperature of the alloy. Finally, the assemblymust be sealed where the conductive bars cross one side wall of thebase.

Objects of the present invention include: the provision of an anodicassembly in which the anodic bars and the embedding may be easilyrecovered without destroying the base of the cell; the provision of ananodic assembly where pure lead may be used as an embedding material;the provision of an anodic assembly which does not require a heatresistant base for extremely high temperatures; and, the provision of ananodic assembly which does not require special sealing means where theconductive bars come out of the base.

In the anodic assembly of the invention, cathodic and anodic elementsare interleaved and supported in a base. The base is an openquadrangular rigid tank of which one of the sidewalls is missing. Theanodic aggregate comprises vertical anodic plates made of graphite,anodic conductive bars, and the fourth sidewall of the base, and saidaggregate without any fastening means is set down on the base. Theanodic conductive bars convey the electric energy to the anodic platesand cross the fourth sidewall of the base. The base is provided with aprotective covering for withstanding the electrolyte and theelectrolysis products, and the anodic aggregate, except the unernbeddedpart of the anodic plates and the projecting parts of the conductivebars, is enclosed in a rigid inert envelope. The tightness between theanodic aggregate and the base is insured when the fourth sidewall fitsinto the base by means of a flexible seal made of a closed cell cellularmaterial laid in a groove provided in the base.

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a perspective view of a base according to the invention;

FIG. 2 is a perspective view of an anodic aggregate which fits into thebase represented in FIG. 1;

FIG. 2A is a sectional view taken along line A-A of FIG. 2;

FIG. 2B is a sectional view taken along line B-B of FIG. 2;

FIG. 3 is a perspective view of the anodic aggregate represented in FIG.2 set down in the base represented in FIG. 1;

FIG. 4 is a detail view of the flexible seal and its receiving groovebefore the anodic aggregate is set down; and

FIG. 5 is a detail view of the flexible seal and groove after the anodicaggregate has been set down.

The anodic assembly illustrated in the drawings is particularly adaptedfor use as part of a diaphragm electrolysis cell used to electrolizeaqueous solutions of sodium chloride and in another electrochemicalprocess. The base, as shown in FIG. 1, is made of reinforced concrete,and is provided with a synthetic resin coating for withstanding thechlorinated brine. The base comprises a structure having a rather squarebottom l and three sidewalls 2. The fourth sidewall 3 (see FIG. 2) isremovable and forms a part of the anodic aggregate. A flexible seal 4,made of a closed cell cellular material for withstanding the chlorinatedbrine, is placed between the fourth sidewall and the base. The seal hasa rectangular cross section and it is laid in the flat bottom groove 5of the base. The sealing edge of the fourth sidewall is provided with anangular ledge 6, having a triangular section, as shown in FIG. 2. Theledge presses on the seal 4 perpendicularly to the bottom of the groove5, and its two oblique faces press the seal against the edges of thegroove 5. Thus, the ledge 6 and the groove 5 combine to provide a veryefficient seal by effectively forming three sealing edges of compressionon the flexible seal 4. That is, sealing edges are formed by pressure ofthe apex of the ledge on the flexible seal 4, and by the pressure ofsaid flexible seal against the comers of the groove 5 as caused by theoblique faces of the ledge.

The anodic aggregate (see FIG. 2) comprises essentially vertical anodicplates 7, anodic bars 9 (see FIG. 2A), embedding metal 10, connectingcrosspieces made of copper 8, and the fourth sidewall 3 of the baseillustrated in FIG. 1. The anodic plates 7 are made of graphite and arealigned in parallel rows. The rows are spaced to let the cathodicelements interleave with them. The bottoms of the anodic plates areembedded in lead 10, and said plates are supported on anodic bars 9which convey electrical energy to the plates. The bars 9 are made ofcopper and are connected with the crosspieces 8 which pass through thefourth sidewall 3. Thus, the anodic aggregate is an alignment ofindependent anodic units each of which comprises a crosspiece 8, ananodic bar 9 two rows of anodic plates 7 and the embedding metal 10, andsaid anodic units are separated at their lower portions by sheets ofplastified polyvinylchloride 11.

With the exception of the crosspieces 8 and the graphite plates 7, theentire anodic aggregate is provided with an exter' nal protectiveenvelope which is made of a charged polyester resin, and whichwithstands the chlorinated brine.

- The fourth sidewall 3, which is integral with the anodic aggregate,encloses strengthening elements 12,13 made or rigid expanded material,as shown in FIG. 2B. These elements 12,13 are laid respectively betweenand above the crosspieces 8, and they confer rigidity to the aggregate.Said elements also provide a saving of polyester resin and make theaggregate lighter. Their dimensions are preferably controlled so thatthe thickness of the polyester envelope is essentially constant, andtensions due to the thermal expansion are thus avoided.

The anodic aggregate and the base are assembled without any bindingmaterial or fastening means. The aggregate is simply set down on thebaseand held in place only by gravitational force. The electrolysisbrine may penetrate without damage between the aggregate and the base,and an effective seal between the fourth sidewall 3 and the base isrealized automatically by the resultant compression of the flexible seal4 when the aggregate is set down. Thus, there is no need to attempt tomake a seal around the crosspieces 8 which make one piece with thesidewall 3.

When the anodic plates are consumed, the anodic aggregate is lifted fromthe basement by simple lifting means and a new one is set down. Thischange does not require any destruction and may be done very quickly.Only the envelope must be destroyed to recover the anodic bars 9 and theembedding material 10 in the anodic aggregate while the base may becontinually reused.

What I claim is:

1. An anodic assembly for electrolysis cells in which anodes andcathodes are interleaved, comprising a base consisting essentially of arectangular bottom and three upstanding sidewalls at three sides only ofsaid bottom, said base having an open side at the fourth side of saidbottom defined by an opening having a bottom edge extending along saidfourth side of said bottom and two inclined side edges sloping up andjoining adjacent sidewalls of said base; and an anodic aggregate setdown on said conductors in conductive relation therewith, embeddingmaterial embedding said conductors and lower portions of said anodicelements to unit them in a unit, a fourth side wall unitary with saidunit and cross-connectors embedded in said material, connecting saidconductors and extending out through said fourth sidewall, said anodicaggregate being set down on said base over said bottom with said fourthsidewall fitting in said opening, and a flexible sealing gasket disposedbetween lower and side edges of said fourth sidewall and said bottom andside edges of said opening to provide a fluid tight seal therebetween,said anodic assembly being removable from said base and replacable by alike anodic assembly.

2. An anodic assembly according to claim 2, wherein said bottom and sideedges of said opening are formed with a channel in which said gasket issealed and wherein the bottom and side edges of said fourth side are ofV-cross section to press into said gasket.

3. An anodic assembly according to claim, 2, wherein saidchannel is ofrectangular cross section.

4. An anodic assembly according to claim 2, wherein said gasket is ofclosed cell cellular material.

5. An anodic assembly according to claim 1, wherein said embeddingmaterial comprises lead.

6. An anodic assembly according to claim 5, wherein said anodicaggregate comprises an assembly of units of which corresponding portionsof said embedding lead are separated from one another by sheets ofplastified polyvinylchloride.

7. An anodic assembly according to claim 1, wherein said base is ofconcrete covered with a synthetic resin coating resistant to chlorinatedbrine.

8. An anodic assembly according to claim 1, wherein said fourth sidewallcomprises strengthening elements of rigid expanded material.

2. An anodic assembly according to claim 2, wherein said bottom and sideedges of said opening are formed with a channel in which said gasket issealed and wherein the bottom and side edges of said fourth side are ofV-cross section to press into said gasket.
 3. An anodic assemblyaccording to claim 2, wherein said channel is of rectangular crosssection.
 4. An anodic assembly according to claim 2, wherein said gasketis of closed cell cellular material.
 5. An anodic assembly according toclaim 1, wherein said embedding material comprises lead.
 6. An anodicassembly according to claim 5, wherein said anodic aggregate comprisesan assembly of units of which corresponding portions of said embeddinglead are separated from one another by sheets of plastifiedpolyvinylchloride.
 7. An anodic assembly according to claim 1, whereinsaid base is of concrete covered with a synthetic resin coatingresistant to chlorinated brine.
 8. An anodic assembly according to claim1, wherein said fourth sidewall comprises strengthening elements ofrigid expanded material.